1. Field of the Invention
This invention pertains to container cooking and cooling systems and more particularly relates to a continuous method and apparatus for cooking and cooling containers with a controlled flow of liquid under superatmospheric pressure while using a minimum amount of heat treatment liquid and when processing the containers either in a still cook or an agitating cook.
2. Description of the Prior Art
Batch type retort systems for cooking and cooling containers such as cans, jars, pouches and trays in water are well known in the art. In order to prevent damage to the containers due to pressure within the containers tending to exceed the pressure externally of the containers, an overriding air pressure is applied over the liquid in these prior art devices.
Although the early types of retorts using heat treatment liquids had problems of uniformly heating each container in the batches of containers since the liquid flow past the outer containers was usually greater than the flow past the containers in the center of the batch, this problem of uniform heat treatment has been solved by the method disclosed in the above mention Mencacci et al U.S. Pat. No. 4,003,302 of which I am a co-inventor. In the Mencacci et al device, containers are loaded into a tunnel and the loaded tunnel is enclosed within a retort. Heat treatment liquid is then circulated past the containers from one end to and through the other end of the tunnel. The liquid is thereafter reheated and recirculated. In order to assure that the uppermost containers in the tunnel are completely immersed in flowing water, the water in the Mencacci et al retort, both within and externally of the tunnel, is maintained at a level above the tunnel. Thus, when changing from the cooking to the cooling cycle the large amount of hot water externally of the tunnel must either be stored in a very large and expensive pressure storage tank, or must be drained and thereafter cold water must be reheated for the next batch resulting in a substantial loss in energy required for heating.
U.S. Pat. No. 3,776,257 to Piegza which issued on Dec. 4, 1973, discloses a high pressure retort with flat walls which separate an article and liquid filled treatment chamber from the outer curved areas of the retort thereby reducing the amount of liquid processing medium required. A gas pressure is applied to the external surfaces of the flat walls to prevent pressure induced bowing of the flat walls.
U.S. Pat. No. 3,389,788 which issued to S. A. Mencacci on June 25, 1968, and U.S. Pat. No. 3,528,827 which issued to R. E. Leslie on Sept. 15, 1970 both disclose pocketed rotors associated with reel and spiral type cookers or coolers which may serve either as rotary pressure preheaters or pre-coolers.